1. Technical Field
The present invention relates to an electrostatic latent image developing toner and a method for producing the same, and an electrostatic latent image developer, a toner cartridge, a process cartridge, and an image forming apparatus.
2. Related Art
In electrophotography, in general, an image is formed through plural processes including electrically forming a latent image on the surface of a photoreceptor (latent image holding member) using a light conductive substance by various means, developing the formed latent image using a developer to form a toner image, followed by transferring the toner image to the surface of a transfer material such as paper, as necessary, via an intermediate transfer medium, and fixing the image by heating, pressurization, heating pressurization or the like. The toner remaining on the photoreceptor surface is usually cleaned by a cleaning process using a blade.
As a fixing technique for fixing a toner image which has been transferred onto the surface of a transfer material, a heat roll fixing method is generally known. In this method, a transfer material, onto which a toner image has been transferred, is inserted between a pair of rolls including a heat roll and a pressure roll and fixed the toner image. Further, as the same type of technique, a fixing method in which one or both of the rolls is replaced with a belt is also known. In these techniques, compared to other fixing methods, a fast image is obtained quickly, and energy efficiency is high due to direct contact with an image.
In recent years, along with the growing demand for savings of energy necessary for image formation, a technique for lowering the fixing temperature of a toner is demanded in order to reduce the amount of energy used for the fixing process, which accounts for a measure of energy usage, and to expand the fixing conditions. Lowering of the toner fixing temperature brings big advantages such as, in addition to the energy saving and expansion of fixing conditions, shortening of the so-called warm-up time, i.e., the latency time until the surface of a fixing member such as a fixing roll reaches the temperature capable of fixing upon switch-on, and enhancement of the service life of the fixing member.
As a method for lowering the fixing temperature of a toner, a technique for lowering the glass transition temperature of a toner resin (binding resin) is commonly employed. However, in the technique, if the glass transition temperature is too low, fine particles readily cause aggregation (blocking). Therefore, it is important to strike a balance between the low temperature fixing property and the prevention of blocking.